1. Field of the Invention
The invention relates to an electrowetting display technology and more particularly to an electrowetting display, a pixel array substrate thereof, and an electrowetting display pixel structure thereof.
2. Description of Related Art
FIG. 1 is a top view showing a conventional electrowetting display. Referring to FIG. 1, an electrowetting display 10 includes a plurality of electrowetting display pixel structures 100. Each of the electrowetting display pixel structures 100 includes a pixel electrode 120, an insulating layer 132, a hydrophobic layer 134, an oily fluid medium 100a, an aqueous fluid medium 100b, and a wall 150. The hydrophobic layer 134 covers the insulating layer 132. The insulating layer 132 is disposed on a surface of the pixel electrode 120. The wall 150 is disposed on the hydrophobic layer 134. Moreover, the oily fluid medium 100a is disposed on a surface of the hydrophobic layer 134, and the aqueous fluid medium 100b covers the oily fluid medium 100a. 
In FIG. 1, each of the electrowetting display pixel structures 100 is applied with a voltage. At this time, the oily fluid medium 100a and the hydrophobic layer 134 contact at a location on the bottom left of each of the electrowetting display pixel structures 100, and the aqueous fluid medium 100b contacts with the hydrophobic layer 134. Generally, the oily fluid medium 100a is a colored hydrophobic fluid medium and the aqueous fluid medium 100b is a transparent aqueous fluid medium. Therefore, after passing through the oily fluid medium 100a, a light is absorbed by the oily fluid medium 100a, thereby displaying the color of the oily fluid medium 100a. On the other hand, the light passes through the transparent aqueous fluid medium 100b. 
Accordingly, when a voltage is applied to the electrowetting display pixel structure 100, the oily fluid medium 100a is compressed and pressed against the wall 150. The electrowetting display pixel structure 100 consequently represents a mode as shown in FIG. 1. On the contrary, when the electrowetting display pixel structure 100 is not applied with a voltage, the oily fluid medium 100a covers the hydrophobic layer 134 uniformly. Here, the light is absorbed by the colored oily fluid medium 100a. Thus, the grayscale variation in display is controlled by converting between the two modes of the electrowetting display pixel structure 100 applied or not applied with a voltage, so that the electrowetting display 10 is capable of displaying images.
The conversion rate of the two modes with the electrowetting display pixel structure 100 applied or not applied with a voltage determines the switching rate when displaying images, and the display quality of the electrowetting display 10 is thus determined. However, if the conversion rate of the two modes increases continuously, a delay effect then occurs during the compression of the oily fluid medium 100a. With the delay effect, as depicted in FIG. 1, a small portion of oily fluid medium 100a remains outside of the location on the bottom left of the electrowetting display pixel structure 100. Furthermore, this delay effect reduces the display quality.